Transport of molecules within a cell and out of the cell requires a complex endomembrane system. Endocytosis occurs when the cell membrane engulfs particles (dark blue) outside the cell ...
A plasma membrane is permeable to specific molecules that a cell needs. Transport proteins in the cell membrane allow for selective passage of specific molecules from the external environment.
This takes place when molecules diffuse across the cell membrane by travelling through specific transport proteins. It occurs down a concentration gradient - molecules move from an area of high to ...
The oxygen diffuses across the partially permeable membrane of the alveoli cells and the capillary wall, into the red blood cells to be carried around the body. Osmosis close osmosisThe movement ...